EFFECTS OF PARTIAL RINGING AND ORGANIC SOLVENT APPLICATION TO RINGED PORTIONS ON GROWTH OF YOUNG PEACH TREES

The effect of partial ringing and treatment with organic solvents on shoot length of one-year-old potted peach (Prunus persica Batsch cv. Akatsuki) trees grafted on a wild peach rootstock was investigated. A 2-cm wide partial ring of bark was removed at a height of 15 cm above the graft union to leave a 2 mm connecting strip. The ringed portions were swabbed with either acetone, ethyl acetate, chloroform, n-butanol or distilled water. Each treatment was replicated five times and a similar number of non-ringed and completely ringed trees were retained as controls. Complete ringing involved bark removal as described above minus the connecting strip. Acetone was the most effective in reducing shoot length followed by chloroform, n-butanol, ethyl acetate and partial ringing alone. Complete ringing had a detrimental effect, as tree growth stopped shortly after treatment and the trees died within four months. Trunk circumference was higher above than below the ring in ringing treatments suggesting carbohydrate accumulation. Complete ringing recorded the highest circumference above the ring. The ratio of the circumference above the ring to that below it was highest in completely ringed trees followed by those treated with chloroform, n-butanol, acetone and ethyl acetate (which had the same ratio) and water respectively. Starch content was higher above than below the ring while mineral content was higher in the roots than the other portions. Organic solvent treatment in addition to partial ringing had an additive effect in shoot growth reduction. A combination of partial ringing and acetone treatment promises to be useful in reducing shoot length in peach.